Velocity gradient and contraction frequency of the pyeloureteral system

Summary An optical detection method, using video imaging, is used to quantitatively record the frequency and velocity profile of the renal pelvis of the rabbit. It is demonstrated that concentric waves originating at the periphery of the pelvis have an initial velocity of 3.2 cm/sec, accelerating toward the pelviureteral junction reaching a final velocity of 6.4 cm/sec.This work was supported by an NIH, grant No. AM 19366.     

Conduction velocity of peristaltic waves in the in vivo ureter: application of a new diameter gauge

Summary The conduction velocity of peristaltic movements of the canine ureter was measured under anaesthesia with a new type of diameter gauge using an image sensor. The peristaltic velocity was 34.1±6.2 mm/sec in 10 experiments. Noradrenaline at a low dosage of 1 g/kg i.v. reduced the resting diameter, increased the conduction velocity to 47–56 mm/sec, and approximately doubled the frequency of contraction. The application of acetylcholine also caused an increase in both frequency and conduction velocity (42–46 mm/sec). A plot of the conduction velocity against the mean period of peristaltic contraction was hyperbolic in shape.     

A possible age-related decrement in the conduction velocity of Aplysia neuron R2.

In late winter and in spring, the conduction velocity of the R2 axon of Aplysia californica is 0.48 m/sec or more in all specimens. However, in the summer, fall and early winter, some sexually mature animals exhibit markedly diminished R2 conduction rates (as low as 0.24 m/sec). It is possible that this reduced velocity is a reflection of the age of the specimen from which the axon is taken.     

Antidromic responses evoked in the central end of the phrenic nerve by stimulation of the ipsilateral dorsal column in the cat]

In 15 adult cats under nembutal anaesthesia the dorsal columns have been stimulated at the level of the first and the second cervical segments. Under these conditions antidromically evoked responses appear both on the ipsilateral radial and phrenic nerves. Some of the afferent phrenic fibres thus activated may be related to the diaphragm muscle receptors. In some experiments a group of thin fibres (conduction velocity comprised between 16-20 m/sec) were also activated.     

Thermal conductivity of wax comb and its effect on heat balance in colonial honey bees (Apis mellifera L.)

Summary Wax comb was found to have a thermal conductivity of 0.36×10^–3 cal/cm sec °C. At low air temperatures, honey bees,Apis mellifera L., form clusters inbetween the combs in their nests. The combs provide insulation and the bee behavior actually increases the insulating effectiveness of the combs. When they form a compact living layer over the wax comb, the conductivity can be reduced to 0.065×10^–3 cal/cm see °C. Some aspects of the role of the wax comb in heat balance are examined in this paper.     

A tonic component in the motility of the upper urinary tract (renal pelvis-ureter)

In isolated muscle strips of porcine renal pelvis and ureter, the calcium antagonist nifedipine (3.10(-7) moles/l) completely suppressed spontaneous phasic mechanical activity and the phasic components of an adrenaline-induced activation (P-component). In the presence of nifedipine, adrenaline induced in pelvis preparations (but not in the ureter) a tonic contraction (T-component) which was on average 61% of the control reaction (SD +/- 26%; n = 35).     

Embryonic cell surface: Electrophoretic mobilities of blastula cells

Résumé La mobilité électrophorétique des couches germinales présomptives d'embryons deXenopus laevis au stade blastula fut mesurée. Les valeurs obtenues ont été 1,38 /sec/V/cm pour les cellules ectodermiques et endodermiques et entre 1,27 et 1,31 pour les cellules mésodermiques, les différences de mobilité furent significatives.

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This work was supported by a grant from the National Research Council of Canada toSara E.Zalik.     

Oscillations in the pigeon's pupil servomechanism in relation to illumination

Zusammenfassung Die oszillatorischen Änderungen der Pupillenweite wacher Tauben wurden infrarot-reflektometrisch gemessen. Gleichzeitig mit einer Amplitudenzunahme steight die Frequenz der Pupillenoszillationen von 1/sec bei einer adaptiven Beleuchtung unter 10 Troland bis auf 15/sec bei 1500 Troland.     

A tonic component in the motility of the upper urinary tract (renal pelvis-ureter)

Summary In isolated muscle strips of porcine renal pelvis and ureter, the calcium antagonist nifedipine (3·10^–7 moles/l) completely suppressed spontaneous phasic mechanical activity and the phasic components of an adrenaline-induced activation (P-component). In the presence of nifedipine, adrenaline induced in pelvis preparations (but not in the ureter) a tonic contraction (T-component) which was on average 61% of the control reaction (SD±26%; n=35).The experiments were supported by a grant from the Deutsche Forschungsgemeinschaft (Go 130/20).     

Eine Methode zur Bestimmung des Endpunktes der Sol-Gel-Umwandlung bei der Plasmagerinnung

Summary In order to measure the clotting time of blood plasma the sol-gel transformation is observed. The process is retarded with mol/18 of 1,4-oxyphenyl-sulfonate. A lowering of the prothrombin content of 50% results in a difference of time against normal values of 45–55 sec., compared with 3–4 sec. with the method ofQuick.     

Frequency gradient in the autorhythmicity of the pyeloureteral pacemaker system

The pacemaker properties of the various regions of isolated segments of the rabbit renal pelvis were examined. The results show that pacemaker frequency and waveform of contraction change significantly within the renal pelvis. The highest frequency was encountered at the fornix, while the ureteropelvic junction is lowest.     

A simple,sensitive, non-stimulated photon counting system for detection of superoxide anion in whole blood

A simple, sensitive, non-stimulated assay was developed to measure the superoxide anion concentration in whole blood, using an ultra-sensitive chemiluminescence (CL) analyzer, and lucignin amplification. The assay system can be performed without leukocyte isolation or stimulant administration. The blood CL levels of healthy males (362.8±337.7 counts/10 sec) were not different from those of females (335±308.7 counts/10 sec) (p=0.64), whereas the CL levels in whole blood in patients with acute pancreatitis (2522±2014 counts/10 sec) were significantly higher than those of healthy controls (p<0.001). This assay system may be valuable in the future for quantitative measurement of reactive oxygen species in various disorders.     

Frequency gradient in the autorhythmicity of the pyeloureteral pacemaker system

Summary The pacemaker properties of the various regions of isolated segments of the rabbit renal pelvis were examined. The results show that pacemaker frequency and waveform of contraction change significantly within the renal pelvis. The highest frequency was encountered at the fornix, while the ureteropelvic junction is lowest.This work was supported by NIH Grant No AM19366.     

Differential effects of the serotonin receptors on cultured rat cerebral cortical neurons

Effects of serotonin (5-HT) on cerebral cortical neurons were examined by patch clamp techniques. 5-HT produced a variety of responses such as outward (19/73 patches/neurons), slow inward (15/73 patches/neurons), fast inward (8/73 patches/neurons), and mixed currents (initially fast inward deflection followed by an outward response: 2/73 patches/neurons), with a latency of 12 sec, 15 sec, 0 sec, and 0 sec respectively, at a holding potential of −60 mV in whole-cell patches. The fast inward currents were again evoked by a selective 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide hydrochloride (CPBG). In the cell-attached patch clamp configuration, 5-HT inside the patch pipette elicited single channel currents with slope conductances of 42 pS and 132 pS (4/42 patches/neurons). CPBG inside the patch pipette evoked inward single channel currents with a lower slope conductance of 41 pS (3/23 patches/neurons). In contrast, application of 5-HT or a 5-HT₂ receptor agonist, α-methyl-5-hydroxytryptamine-maleate, outside the patch pipette induced outward single channel currents with a major slope conductance of 140 pS (8/30 patches/neurons) or 135 pS (6/20 patches/neurons), respectively. These results indicate that the outward and fast inward currents may be mediated respectively by the 5-HT₂ receptor, which is coupled to a G-protein, and by the 5-HT₃ receptor, which contains the non-selective cation channel, and that the mixed type may be caused by both the 5-HT₂ and 5-HT₃ receptors. Received 27 September 1996; received after revision 4 November 1996; accepted 7 November 1996     

Sympathetic regulation of collecting vein

Zusammenfassung Die nach Durchtrennung des Truncus sympathicus (LG₃-LG₄) beim narkotisierten Hunde eintretende Dilatation der Vena femoralis erreicht in 30 sec ihr Maximum. Nach sukzessiver Abnahme beträgt der stabilisierte (in 10 min) Durchmesser 109,6% des Ruhediameters. Reizung des distalen Grenzstrang-Stumpfes bewirkt frequenzabhängige Diameterabnahme. Maximale Konstriktion (bis zu 12,7%) wird durch 15 imp/sec Reizung hervorgerufen.     

Electrical slow waves in oviductal smooth muscle of the guinea-pig,mouse and the immature baboon

Summary Oviducts of the guinea-pig, mouse and immature baboon show prominent electrical slow waves. In the guinea-pig oviduct they are 40–50 mV in amplitude and have a duration of 1.5 sec in the isthmus. Slow waves in these tissues propagate at a speed of 1–13 mm/sec.Decreased 6th December 1977.Supported by NIH-09339-02 and Rockefeller Foundation. A. T. was a Rockefeller Foundation Fellow. Correspondence to B. J. Hodgson, Dept. Obstetrics and Gynecology, UTHSCSA, San Antonio, Texas 78284.     

Determination of the time of fast rejoining processes after γ-ray fractionated exposures inNigella chromosomes

Résumé Des graines sèches deNigella damascena ont été irradiées par les rayons du⁶⁰Co à des doses fractionnées (2×4 Krads) séparées par des intervalles de temps compris entre 2 et 4 minutes et croissant de 10 en 10 sec. On a prouvé qu'une diminution très significantive des taux d'aberrations chromosomiques se produit entre 2 min 10 sec et 2 min 20 sec. Lorsque les graines sont préalablement traitées par un agent de chélation (diéthyldithiocarbamate), on observe au cours d'une expérience strictement parallèle, un accroissement hautement significatif des taux d'aberrations se produisant exactement au même moment. Ces expériences confirment en les précisant les résultats d'expériences antérieures.

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Aspirant du Fonds National de la Recherche Scientifique.

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The author is thankful to the Belgian Government for awarding O.C.D. research fellowship. Present address: Bhabha Atomic Research Center, Trombay (Bombay) India.     

Über eine bei jungen Kaninchen während Erregung auftretende hochfrequente mesenzephale Bursttätigkeit

Summary In the mesencephalon of young rabbits (11–45 days old), a distinct pattern could be elicited by emotional activation: it consists of high-frequency bursts (48–70 c/sec, duration up to 150 msec), superimposed on phase-locked slow waves.     

Satellite DNA (II) from sea urchin (Lytechinus variegatus) sperm

When DNA isolated from freshly collected sperm of sea urchin (Lytechinus variegatus) is centrifuged to equilibrium in CsCl, 2 heavy satellite bands appear beside the main band DNA. Satellite DNA (II) appears in between the main band DNA (rho = 1.695 g/cm3) and the rDNA satellite (rho = 1.722 g/cm3). Satellite DNA (II) has a buoyant density 1.710 g/cm3, corresponding to 50% GC content. It is speculated that the satellite DNA (II), which appears to be of high mol. wt, might contain the sequences complementary to histone mRNA.     

Does an initial phasic response exist in the receptor potential of taste cells?

The depolarizing receptor potentials to 0.5 M NaCl recorded from frog taste cells did not exhibit any phasic response, even when the rectangular waveform of stimulus onset was employed. The quickest depolarizations recorded reached the peak in 50 msec. On the other hand, the gustatory neural response showed initial overshoot of the impulse discharge even when 0.5 M NaCl was delivered at the slower rate of 0.06 ml/sec. It is concluded that the initial neural response may be associated with the rate of rise of the receptor potential before its plateau level is reached.